Unsymmetrical oxonol filter and antihalation dyes



Patented Dec. 12, 1950 UNSYMMETRICALV OXONOLV FILTER- 'AND ANTIHALATION DYES Grafton H; Keyes/ana Leslies;sifigkenoeh; e'ster',Vl N." Yg, assignors to Eastman 'KodakiCom'' pany, Rochester,-N; Y., a corporation of New Jersey Appli-cation January 1.7, 1947, Serial No`722,740

invention relates' to improvements* in photographic elements having light screening substances therein.

It isN known that photographic elements require, for many purposes, to have light screeninlg'fl substances incorporatedv therein. Sucha light screening substance may be in a'layer overlying a light sensitive emulsion or overlying two or more light sensitive emulsions; or it may be in a light sensitive emulsion fcr'the purpcseofmodifying-a light record in such emulsionV or of` protecting an underlying light sensitive emulsion or emulsions from the actionof lightl of wave length absorbed by such light screening' substance; or it may be in a layer not ccnitainingl a' light sensitive substance but arranged between two light sensitive emulsions; or it may bein a'r layer serving as a backing on anelement'hav-l ing one or ymore light sensitive emulsions' (for example, t reduce halation).

In particular, light screening substancesja-re'- e. g. to protect red andgree'n-sensitized emule`v sions' from'the action ofv blue lightandv (c) inl backings, forming the y*so-"calledE anti-halation'f layers, on either side of a transparent support' carrying the' light-sensitive emulsion or' emul-y sions. v v

In most cases, and especially whenthe' element contains a color-sensitizedi emulsion' or' colorsensitized emulsions, it is. particularly desirable to employ light-screening'substances which do not aifect the general sensitivity or the color sensitivity of light-sensitive vemulsions with which they may come into contact. It is also" particularly desirable to employ light-screening substances which do not substantially diffuse from the layers or coatings in which they are incorporated,A either during'the manufacture ofk the element or 0n keeping it or in photographically processing it. Fnally, it is generally necessary to employ "light-screening' substances which can 'readistroyed and removed, pribr'to' enduring' Ofafter one of the'photo'grapnic'baths"employed*inproc:

essing the element after exposure, e. g. a photoV graphic developing bath or fixing bath or a silveroxidizing (including silver-removing)A-` bath. For

example, in Ian element which is togbeprocessed by reversal; itis' oftennco'n'venient'to employ a light-screening substance which is rendered ineiective by the developer employed to develop the latent image or' images" to silversincevll exposure tc'li'ghtf'of' the' residual light' sensitive emulsionor'emulsi'ons mayth'ereby'be facilitated. This is particularly the"'casef'when,'V in making color pho'f` tcgraphs, several' differentially color-sensitized emulsions, constituted; for example, by silver 'halide',` such "assilver'bromide 'dispersed in gelatin, c'ollc'dionor other colloid; are'ccatedon` one or both" sides of a support, for' example in inseparablysuperimposed`layers; Such diiierentially color-sensitized emulsions have to be processed to different colors andto facilitate the differential color-processing,` methods 'involving selective e-Xposurefof light sensitive images in the layers may be employed. Such selective 1re-exposure, e. g. of silver halidec remaining undeveloped -in development of the latent images formed in silver halide emulsion layers (residual silver halide) is' oftenv facilitated' if the light-screeningr` substance whichwas 'pre'sent Yduring'y the original ex'# po'su'r'e l is 4d`e1coloriz`ed`-or removed in 'thedevelop' ing bath employed to develop the latent images" tos'il'ver; Any'o-ftl'e elements'referr'ed-to above maybesucnthat onefor-more of the emulsions contain' vcoupling cmponents e. g; those described' in French Patent 834,371, granted" August 16", 1938;'

catedabcve'. Many-'of` these" are known yellow dyes but ithasproved 'extremely difficult tcnd' dyes vhaving; thecombinatin'cf qualitiesv desired.'

Many arjeinot: resistant' to diffusion and wander rather" freely from' the layerin" which it is in"- tendedtliat they 'should "remaini many, adversely aifect the sensitivity of light' sensitive emulsions with which they come` into Icontact (a number of these reduce the general sensitivity or Some specie color sensitivity thereof, but others of them.v mayeven impart an additional and unwanted specific color'v sensitivity thereto) We have newfound a class of dyes which sate'V isfa'ctorily fu'liill the' requirements of filter andr antihalation dyes for usefin'photographic elements. `Thisclass consists of certainv unsymme'trica'l, methineoxnol and polymethine'o'inol dyes. Thesedyes are'chara'ct that they contain' the oio'clii'r'nie atorisY O"= and -OH connected by a conjugating chain of car` bon atoms. We propose to use dyes in which one end of the conjugated carbon chain is connected t a barbituric acid, thiobarbituric acid, pyrazolone, oxindole, indandione or isoxazolone ring and the opposite end of the chain is connected to a cyanoacetyl benzofuran or benzoyl acetcnitrile group.

In the drawing, the iigures are enlarged sectional views of photographic elements showing overcoating filter and anti-halation layers according to our invention.

The compounds which we propose to use as screening dyes have the following general formula:

where X represents the atoms necessary to complete a barbituric acid, thiobarbituric acid,

pyrazolone, oxindole, indandione or isoxazolone ring, Y is an aryl nucleus of the benzene series or a benzofuran group and 'n is 0, 1 or 2.

The general formula indicates that our cornpound may be depicted in two electromeric forms.

The following examples illustrate compounds 3.,"

which may be used according to our invention.

3.45 g. (l mol.) of Il-(3acetanilidoallylidene) 3-methyl-1-phenyl-5-pyrazolone, 1.7 g. (1 mol.) of 2,4-dimethylbenzoylacetonitrile, cc. of pyridine and 1 g. (1 mol.) of triethylamine were reuxed for l5 minutes. chilled and then acidied with hydrochloric acid. A tarry mass separated. After decantation of liquors the somewhat tarry residue was stirred up in presence of a small amount of methyl alcohol and soon became crystalline. It was collected on lter, washed with methyl alcohol and dried. It was puriied by dissolving in methyl alcohol as the triethylamine salt, filtering hot, acidifying and chilling. After two such treatments the dye was obtained as brownish orange crystals, M. P. 139-141" with decomposition. The pinkish orange solution of the triethylamine salt was bleached by developer.

[2-cyanoacctyZbeneofurmzl [1,3-dz'ethylba1ibturic acz'd- (5) l-pentamethzneoxonol 3.8 g. (1 mol.) of 2-(5-acetanilid0-2,4pentadi enylidene cyanoacetyl) benzofuran, 1.85 g. (1 mol.) 1,3-diethylbarbituric acid, cc. of pyridine The reaction mixture was f '2-cyanoacetylbenzofuran, 30 cc. of absolute ethyl NieQi-C@ and 1 g. (1 mol.) of triethylamine were heated together at the temperature of a steam bath for 10 minutes. The mixture was then chilled and made acidic with dilute hydrochloric acid. The dye which separated was collected on lter, washed with methyl alcohol and dried. It was purified by dissolving as the triethylamine salt, filtering hot and then acidifying and chilling. Two such treatments gave the dye as a dark purplish solid, M. P. -197 With decomposition. The blue solution of the triethylamine salt was bleached by developer.

The 2-(5-acetanilido-2,4-pentadienylidine cyanoacetylbenzofuran employed in the above preparation was made by reiiuxing a mixture of 3.7 g. (l mol.) of 2-cyanoacetylbenzofuran, 5.5 g. (l mol.) of glutaconic aldehyde dianilide hydrochloride, 25 cc. of acetic anhydride and 1.65 g. (1 mol.) of fused sodium acetate for 2 to 3 minutes. The product separated on chilling, it was collected on lter, washed with water and methyl alcohol and used without further purication.

EXAMPLE 3 [Z-cyanoacetylbeneofuranl [3-methyZ-1-p-sulfophenyl-5-pyrazol0ne-(4H trimethineoxonol 1.7 g. (1 mol.) of 2-(3-acetanilidoallylidenecyanoacetyl) benzofuran, 1.3 g. (1 mol.) of 3- methyl-1-p-sulophenyl-5--pyrazoloney 20 cc. of pyridine and l g. (2 mol.) of triethylamine were mixed together and heated on steam bath for l5 minutes. Dye separated from the chilled rcaction mixture on treatment with excess of dilute hydrochloric acid. The crude, Washed dye was puried by dissolving the dye in hot alcohol as the triethylamine salt, filtering hot and precipitating from the chilled filtrate on acidiiication. Two such treatments gave the dye a5 a brownish crystalline powder M. P. 240-242 C. dec. Its bluish red solution of the triethylamine salt was readily bleached by developer.

The 2-(3-acetanilidoallylidine cyanoacetyl) benzofuran employed in the above was made by refluxing a mixture of 3 g. (1 mol.) of 2cyano acetylbenzofuran, 5.2 g. (1 mol.) of -anilino acrolein anil hydrochloride, 20 cc. of acetic anhydride and 2 g. (1 mol.) of triethylamine for 15 minutes. The product separated on chilling and was collected, Washed on the lter and used without further purification.

EXAMPLE 4 3.2 g. (1 mol.) of 4-acetanilidomethylene-3- methyl-1phenyl5pyrazolone, 1.85 g. (1 mol.) of

alcohol and 2 g. (2 mol.) of triethylamine were refluxed together for a period of one hour. Dye separated from the chilled reaction mixture on acidincation. Crude, washed dye was purified by egresada@ V recrystallizationf as the triethylamnef salt-v and precipitationzwithacid. The dye was' obtained as yellow crystals, M. P. lil-143 C. with decomposition. Its solution is yellow.

EXAMPLE5 @Alle [ZL'cyanoacetyZbenaofumnl [1 ,3dz'phenyl b'arbituric acid'- 5) l tm'methineoonol 4.1 g. (l mol.) of 5-(3-acetanilidoallylidine) 1,3-dipheny1 barbituric acid, 1.8g, (1 mol.) of 2cyanoacetylbenzofuran, 40 cc. of pyridine and moz-OQJJ- 2 g. (2 mol.) of triethylamine were heated together under reflux for minutes. Dye separated from the chilled reaction mixture-on acid- The i ication v with dilute hydrochloric acid. crude, washed dye Was purified by recrystallizaf tion as the triethylamine salt and precipitation` 1t Was obtained as brownishy on acidication. crystals, M. P. 224-226 C., With` decomposition.

Itgive a bluish red solution in alcohol and triethylamine vand was bleached readilyby developer.

barbituric acid employed above Was made by reuxing together equimolecular portions of 1,3- diphenylbarbituric acid, -anilino acrolein anil hydrochloride and triethylamine in the presence of acetic anhydride for 30 minutes. Theproduct separated on chilling and was collected, washed on filter and used without further purication.

EXAMPLE 6 @se [2-cyanoacctylbenzofuran] [3-methyZ-1 -goheney 111-5 -pyrazolone- 4 l iimethmcoxonol 3.45' g. (1 mol.) of 4-(3-acetanilidoallylidine) 3-methyl-1phenyl5pyrazolone, 1.85 g. (1 mol.) of 2-cyanoacetylbenzofuran, 20 cc. of pyridinel and 1 g. (1 mol.) of triethylamine were reiiuxed' together for ten minutes. Dye separated from the chilled reaction mixture on treatment With excess of `dilute hydrochloric acid. The crude Washed dye Was purified by dissolving in alcoholv as the triethylamine salt, filtering hot and precipitating from the chilled filtrate on acidification. Two such treatments gave the dye as very dark, purplish crystals, M. P. 24T-244 C., with decomposition.

EXAMPLE '7 HaCz-N-C O CN 65 [2 -cyanoacetylbeneofr'aitl #['1 ,i3-diethyZ-2-thobarbiturz'c acz'd- 5) l pentamethineoxonol v2 g. 1` m01.) of 5-r5-acetani1ido 2A-parliamenylidine) 1i3-rdiethyl-Z-thiobarbituric acid, 0.9"g.

5- (1 m01.) of 2-cyanoacety1benzofuran, 2o ce. of

pyridine and 1 g. (2 mol.) of triethyla'minewer'e mixed together and stood at room temperature for l5 minutes. Dye separated from this reaction mixture on :chilling and acidiication with dilute hydrochloric f acid; The "crude, Washed `dye"'was puried by dissolvingin methyl alcohol as the triethylamine salt, lteringhot and precipitating frommthei'chilled-ltrate on acidication.- Twosuch treatments gavethedye as aI very darkr solid M. P. -187 C., With decomposition. The solution of the triethylamine salt was bluish red, readily bleached.

EXALIPLES anilide hydrochloride, sodium acetate in aceticV anhydride. The Yproduct separated'on chilling? andV was collected,` washed on lter vand used! Without further purification. The 2-cya`noacety'l- 5'phenylbenzofuran employed above was made ina manner similar to that described by Burger and Dienet, J. A. C. S. 67, 569 (1945)A in making' a cyanoacetylbenzofuran.`

EXAMPLE 9 mcg-N co so; omen-omcH-cmoH-oc(om-O s moeite-co oN l [Benzoylacetontrzlel [1,3-diethyl-2-triobarbi turzc acid( 5 l-pentamethineoonol 2 g.-v (1 mol.) of 5#(-acetanilido-ZA-penaf dienylidine) 1,3diethyl 2 L- thiobarbituric acid, .'I'g. (l m01.) of"benzoylacetonitrile, 20 ccf of pyridine'and 1 g."(2 mol.) of triethylamine were mixedtogether 4and stood at roomtemperature for 15 minutes.- f Dye separated from this reaction mixture on chilling and acidification with dilute hydrochloric acid. The crude; Washed dye was purified in the usual way and obtained as very -darkcrystala yMFP. 164-166by C., with decomposition. The solutionof the' triethylamine" salt was purple, readily bleached.

` EXAMPLE lZ-cyanoacetylbenzofuran] [1 -ethyloacz'ndole- (3) l-pentamethineocconol 3.8 g. (1 mol.) of 2-(-acetanilido-ZA-pentadienylidine cyanoacetyl) benzofuran, 1.6 g. (1 mol.) of l-ethyloxindole, cc. of pyridine and 1 g. (1 mol.) of triethylamine were mixed together and heated at steam bath temperature for 10 minutes. Dye separated from the chilled reaction mixture on acidication with dilute hydrochloric acid. The crude, washed dye was puried in the usual manner and obtained as a dark brown felt. M. P. 189-l9l C., with decomposition. This solution was blue.

EXAMPLE 11 4.4 g. (1 mol.) of 5-(5-acetanilido2,4-penta dienylidine) 1,3 di methoxyethylbarbituric acid, 1.85 g. (1 mol.) of 2-cyanoacetylbenzofuran, 20 cc. of pyridine and 1 g. (1 mol.) of triethylamine were mixed together and heated at steam bath temperature for ten minutes. Dye separated from the reaction mixture on chilling and acidication with dilute hydrochloric acid. The crude, washed dye was purified in the usual manner. It was obtained as purplish brown powder, M. P. 16S-168 C., with decomposition.

The 5-(5-acetanilido-2,4 pentadienylidine) 1,3-di--methoxyethylbarbituric acid employed above was made by refluxing a mixture of equimolecular portions of 1,3-di--methoxyethylbarbituric acid, glutaconic aldehyde dianilide hydrochloride, fused sodium acetate in acetic anhydride for 2 to 3 minutes. The product separated on chilling, collected and washed on lter and used without further purification.

The 1,3-di(-methoxyethyl) barbituric acid employed above was made according to the method used by Whitely J. C. S. 91, 1338 (1907) in preparing 1,3-diphenylbarbituric acid. The 1,3-di(methoxyethy1) barbituric acid was obtained as colorless crystals melting at 5960 EXAMPLE 12 Biol-0 N-C o [3-carboymethyl 1 phenyl--pyraeolone-(4) l [2 cyanoacetylbenzofuranl pantamethineoiconolA 3.8 g. (1 mol.) of 2-(5acetanilido2,4penta dienylidine cyanoacetyl) benzofuran, 2.2 (1 m01.) of 3-carboxymethyl-1-pheny1-5-pyrazolone, 20 cc. of pyridine and 1 g. (1 mol.) of triethylamine were reuxed together for 10 minutes. Dye separated from the chilled reaction mixture on acidii'lcation with dilute hydrochloric acid. The crude washed dye was puried in the usual manner and obtained as very dark, almost black, crystals, M. P. 15S-156 C., with decomposition. The solution was blue.

EXAMPLE 14 [2-cya1zoacetylbenzo fumnl 3-methyl-1 -p-tolyl- 5-pymzolone- (4) l-methz'neoonol fais-'sauve 9 [2-cyanoacetylbenzofuranl [I-'z'nandione-(Z) l pentamethz'neoonzol 3.8 g. (1 mol.) -of 2-Gacetanilido-2,4pentadienylidine cyanoacetybbenzofuran, 1.5 g. (1 mol.) of 1,3-indandione, 20 cc. of pyridine and l g. (1 mol.) of triethylamine @were =mixed "to'ge'tl'ier 'and :heated at steam bath temperature iol' Tl0 minutes. Dye 'separated from "the f'chilled vrreaction mixture on treatment v.with 'excess'of dilute .hydrochloric acid. Thecrude, washed .dye was purified :inthe usual i manner and obtained fas *a `black powder, M. I P. 18S-187 C., with decompo- 3.8 g. (1 mol.) of 2-(5acetanilido-2,4pentadienylidine cyanoacetyl) benzofuran, 1.6 g. (l mol.) of 3-phenyl5(4)isoxazolone, 30 cc. of pyridine and 1 g. (l mol.) of triethylamine were mixed together and heated at steam bath temperature for 15 minutes. Dye separated from the reaction mixture on chilling and acidification with dilute hydrochloric acid. The crude, washed dye was puried in the usual manner. It was obtained as minute dark crystals, M. P. 191- 193 C., with decomposition.

For the preparation of filter layers from 5 milligrams to 25 milligrams of dyes are wet with 2 cc. of triethylamine or pyridine and dissolved in -20 cc. of methanol, acetone or other watersoluble miscible solvent. The solution is added to 100 cc. of 3% to 6% aqueous gelatin solution at 40 C. After adjusting the pH to its optimum value, the dye solution is coated on the support which may already have other photographic layers.

The preparation of lter layers may be illustrated by the following examples.

The lter solutions are made up much asin the two following examples.

(1) A 20 mg. portion of [2-cyanoacetylbenzofuran] [3-methyl-l-p-sulfophenyl--pyrazolone- (4)l trimethineoxonol is wet with 1 cc. of Dyrdine and dissolved in cc. of methanol. This solution is added to 50 cc. of 10% aqueous gel containing mg. of polyvinyl pyridine metho-ptoluene sulfonte. Water is added to bring the volume to 100 cc. (=5% gel) and the pI-l is adjusted to 5.7. The solution is then ready for coating on the support.

(2) A 12 mg. portion of [2-cyanoacetylbenzofuranl [1,3-di--methoxy ethylbarbituric acid- (5)] pentamethineoxonol is wet with 1 cc. of pyridine and dissolved in 20 cc. of methanol. This solution of dye is added to cc. of 10% aqueous gel. Water is added to bring the volume to 100 cc. (=5% gel) and the pH is adjusted to 6.0. The solution is then ready for coating on the support.

In the accompanying drawing, the various gures are enlarged sectional views of photographic elements having lter layers or anti-halation layers made according to our invention. As shown in Fig. 1, a support AIt of any suitable in aiteriallislich 'iaSr-'jeeiluiose mtfatfe, '1cel11osefaetate synthetic res'inous lmaterial or l-'opaque l'material such as paper is coated with an emulsion layer I I and an overcoating layer I2 containing an unsymmetrical methine or. .polymethine oxonol dye according to' our iriveniton.

Fig. 2 illustrates a multi-layer photographic .element for color photography-in ywhichthe sup'- port -IIlv is` coated with sensitive layers I3, fl 4 vfand I5 which record, respectively, the red, fgreenand blue regions-of the spectrum. Between theemulsion layers I4 and I5 `there is va'lltez;layer =I6 containing'a'yellow methine or polymethin'e 'oxonol dye. This lter layer serves'a purpose Well known in color photography of ypreventing exposure of a lower layer of the element by light which the lter layer absorbs. The dye may also absorb liglt-in=other 'regionsisuchas the ultraviolet region of the spectrum.

Fig. y3 represents alm having an anti-yhalation Ilayer' containing "an oxonol j dye according u'to four invention. As "shown therein, the support IIl-c;f

Y ries an emulsion 'layer II "on kone yside and.' an anti-halation layer I3 'containing "an oxonol *dye io'r'rthe opposite side.

As stated above, the oxonol dyes areffoundjto be useful inlte'ror'anti-halation laitiers. The dyes in general are dissolved in Water as the sodium, pyridinium or triethylamine salt, or in organic solvents such as alcohol or acetone and then dispersed in gelatin or other protein or synthetic vehicle such as polyvinyl alcohol.

The dyes used according to our invention have a number of advantages. They may contain acidic groups such as carboxylic acid or sulfonic acid groups and may therefore be mordanted by addition of equivalent amounts of cations such as Pb++, Ca++, Ba++, etc., or organic agents such as polyviny1 pyridine metho-p-toluene sulfonate and other high molecular weight quaternary salts. Since the dyes are unsymmetrical, they may contain only a single acid group and are frequently easier to mordant than dyes containing two or more acid groups.

A further advantage of the unsymmetrical dyes is that they permit the choice of a wider range of spectral absorptions and thus give a better chance of meeting specic requirements of absorption maxima and distribution of absorption properties. The dyes are bleached in the usual photographic processing solutions such as develd Where X represents the atoms necessary to complete a ring selected from the class consisting of barbituric acid, thiobarbituric acid, pyrazolone, oxindole, indandione and isoxazolone, Y represents a group selected from the class consisting of aryl groups of the benzene series and benzofuran, and 1L is a digit from 0 to 2.

2. A photographic element comprising a support having thereon at least one sensitive silver l 1 halide emulsion layer and a light-absorbingl layer containing a dye having the formula:

where X represents the atoms necessary to complete a barbituric acid ring, Y represents a benzofuran ring and n is a digit from 0 to 2.

3. A photographic element comprising a support having thereon at least one sensitive silver halide emulsion layer and a light-absorbing layer containing a dye having the formula:

.where X represents the atoms necessary to complete a pyrazolone ring, Y represents a benzofuran group and n is a digit from 0 to 2.

4. A photographic element comprising a support having thereon at least one sensitive silver halide emulsion layer and a light-absorbing layer containing a dye having the formula:

GRAFTON H. KEYES. LESLIE G. S. BROOKER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,186,608 Keyes Jan. 9, 1940 2,274,782 Gaspar Mar. 3, 1942 

1. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT HAVING THEREON AT LEAST ONE SENSITIVE SILVER HALIDE EMULSION LAYER AND A LIGHT-ABSORBING LAYER CONTAINING A DYE HAVING THE FORMULA: 